February 17, 2014. Difficulty rose by +19.39% to 3.13B from 2.62B.
Change
+19.39%
New difficulty
3.13B
Period length
11.7 days
Network hashrate then (7-day)
0.0 EH/s
Bitcoin price then
$624
Hashprice then
$102,736/PH/day
The 2,016 blocks before it took 11.7 days instead of 14, so the network had more hashrate than the difficulty assumed, and difficulty rose by 19.39%: one of the largest adjustments on record. For every machine on the network that is a pay cut of the same size until the next retarget.